Boron containing fuels



3,070,472 Patented Dec. 25, 1962 3,070,472 BORON CONTAINING FUELS Folsom E. Drummond, Washington, D.C., assignor to The Commonwealth Engineering Company of Ohio, Dayton, Ohio No Drawing. Filed Aug. 3, 1959, Ser. No. 830,985 6 Claims. (Cl. 149-22) This invention relates to improved fuels and methods for increasing the calorific value of fuels, especially those comprising powdered lower atomic weight elements such as boron, beryllium and lithium.

The invention is particularly useful in providing a fuel which is composed of powdered metal and oxygen-supplying agents which upon burning release a large amount of heat as measured in B.t.u. per pound of fuel burned.

It is an object of this invention to provide a fuel which, in the form of a solid fuel, is useful as a propellant for missiles, rockets, and for releasing high temperature gases upon burning. The solid fuel of the invention further may be used as a fuel for jet-driven aircraft, turbines, and the like, as employed in the fields of aviation, military equipment and rail transportation operations.

These and other objects and advantages of the invention will become apparent to those skilled in the art from the following description of the invention.

The persent invention is based upon the provision of a solid fuel of the character described and which is composed of a mixture of low atomic weight metals and their compounds together with oxygen-supplying material to promote the combustion once started.

The invention is illustrated further by the following typical examples:

Example I Percent by weight Diborane 50 Beryllium metal powder (particle size, lmicrons) 30 Lithium perchlorate 20 Example 11 Pentaborane 40 Beryllium metal powder (Ex. I) 35 Lithium perchlorate 25 Example III Decaborane 60 Beryllium metal powder (Ex. I) 30 Potassium chlorate Example IV Diborane 40 Beryllium metal powder (Ex. I) 20 Cellulose nitrate 10 Lithium perchlorate 30 Example V Diborane 45 Boron metal powder (average size, 1 micron) 30 Lithium perchlorate 25 2 Example VI Diborane 25 Lithium metal powder (average size, 1 micron) 50 Lithium perchlorate 15 Preferably the solid fuel mixture of borane (in liquid state) is suitable admixed with metal powder and chlorate material and compressed (2000 psi.) to a solid fuel mass. The temperature of the mixture is kept low enough so that the borane compound used is liquid at atmospheric pressure. Where desired, the fuel mixture may be prepared in the form of a pasty mass by mechanically mixing and blending the ingredients together. The fuel thus compacted may be ignited by an electrically heated wire partially embedded in the mass.

Borane (boron-hydrogen) and powdered low atomic weight metal constitute the essential constituents of the fuel. Oxygen is supplied for supporting the combustion by the chlorate. Other decomposable compounds which release oxygen to promote the combustion of the borane and metal, where desired, may be used.

Boron burned as diborane (B H which is liquid at -ll2 C. at atmospheric pressure, releases approximately 35,000 B.t.u.s per pound of the borane burned. Pentaborane (B H which is a colorless liquid at ordinary temperatures, is highly combustible and is handled at low temperatures (-46 C.) or at temperatures and pressures to maintain it liquid.

Where the fuel is desired to have a lower density or greater porosity, combustible fillers, such as cellulose cotton, e.g. cellulose nitrate or acetate or the like may be incorporated. Such a filler addition is exemplified in Example IV supra. The proportion of constituents may be varied to produce the desired burning rate and calorific value as required. By increasing the propertionate amounts of borane and low atomic weight powdered metal in the fuel, higher B.t.u. values are obtained. A preferred range of borane, powdered metal and chlorate in the fuel, based on the total weight of the fuel mass, is borane 20-60%; powdered low atomic weight metal 30-50%; and chlorate 25-40%.

Beryllium, which has an atomic weight of 9.02 when burned in metal powder form, releases approximately 28,000 B.t.u. per pound of metal burned. Boron, which has an atomic weight of 10.82 when burned, releases approximately 25,000 B.t.u. per pound of metal burned. Lithium, having an atomic weight of 6.94 when burned, releases about 18,000 B.t.u. per pound.

Oxygen is supplied by the use of a chlorate and preferably use is made of a low atomic weight metal perchlorate such as lithium perchlorate. The perchlorate release approximately 60% of the compound upon decomposition as oxygen which sustains the combustion of the fuel mixture.

The meaning of the term low atomic weight in this specification refers to elements having an atomic Weight below 12, and exemplified by boron, beryllium and lithrum.

Powdered mixtures of the fuel may be ignited in the conventional matter or use may be made of a spark plug, electrically heated wire or fuse insert as desired.

It is understood that various materials may be substituted for those set forth in the above examples when the same perform the same function and like results, and the proportionate amounts of the constituents may be varied to suit the use being made of the fuel. Such changes and variations are deemed to be contemplated as coming within the scope and spirit of this invention, the same being more particularly set out in these appended claims..

What is claimed is:

1'. A fuel having increased calorific value and useful as a propellant for missiles and rockets, said fuel consisting essentially of the following constituents in parts by weight, 40 to 60% of a boron hydride selected from the group. consisting of diborane, pentaborane and decaborane. and mixtures thereof, 30 to- 35%. of. a powdered. material. selected from the group of. elements consisting of boron, beryllium and lithium and mixtures thereof, and to 25% of a chlorate selected from the group consisting of potassium chlorate andv lithium perchlorate and mixtures thereof.

2. A fuel having increased calorific value and useful as a propellant for missiles and rockets, said fuel consisting essentially of the following constituents in parts by weight, 40 to 60% of diborane, 30 to 35 powdered beryllium, and 10 to 25% of lithium perchlorate.

3. A. fuel having increased calorific value and useful as a propellant for missiles and rockets, said'fuel consisting essentially of the following constituents in parts by weight, 40 to 60% of pentaborane, 30 to' 35% powdered beryllium, and 10 to 25 of lithium perchlorate.

4. A fuel having increased calorific value and useful as a propellant for missiles and rockets, said fuelconsisting essentially of the following constituents in parts by weight, 40 to 60% decaborane, 30 to 35 powdered beryllium, and 10 to of potassium chlorate.

5. A fuel having increased calorific value and useful as a propellant for missiles androckets, said fuel consisting essentiallyof the following constituents in parts by weight, 40 to 60% diborane, to powdered boron, and 10 to 25% lithium perchlorate.

6. A fuel having increased calorific value and useful as a propellant for missiles and rockets, said fuel consi s'ting' essentially of the following constituents in parts by weight, 40 w diborane, '30 to 35% powdered lithium metal, and 10 to 25% lithium perchlorate.

References Cited in the file of this patent Zaehringer: Missiles and Rocket'sfl vol. 4, No. 6,. Aug. 11,1958, pp. 28, 29,. 31, 32, 34 and 37.

Chem. and Eng. News (1), Ian. 6, 1958, pp. 79-81.

Chem. and Eng. News (H), May 27, 1957, pp. 18-23. 

1. A FUEL HAVING INCREASED CALLORIFIC VALUE AND USEFUL AS A PROPELLANT FOR MISSILES AND ROCKETS, SAID FUEL CONSISTING ESSENTIALLY OF THE FOLLOWING CONSTITUENTS IN PARTS BY WEIGHT, 40 TO 60% OF A BORON HYDRIDE SELECTED FROM THE GROUP CONSISTING OF DIBORANE, PENTABORANE AND DECABORANE AND MIXTURES THEREOF, 30 TO 35% OF A POWDERED MATERIAL SELECTED FROM THE GROUP OF ELEMENTS CONSISTING OF BORON, BERYLLIUM AND LITHIUM AND MIXTURES THEREOF, AND 10 TO 25% OF A CHLORATE SELECTED FROM THE GROUP CONSISTING OF POTASSIUM CHLORIDE AND LITHIUM PERCHLORATE AND MIXTURES THEREOF. 